Feed control mechanism



Feb. 15,. 1944. N. 'r. HOLMBECK FEED CONTROL MECHANISM Filed Oct. 8,1942 :5 Sheets- Sheet 1 HUGH-1 ZZZ-"1. lye-4s Humvee-ck."

N. 'r. HOLMBECK 2,342,049 FEEQOONTROL'MECHANISM Filed Oct. 8, 1942 3Sheets-Sheet 3 v 3 k 7 ll i. .i. m

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Patented Feb. 15, 1944 UNITED STATES PATENT OFFICE 2,342,049 I FEEDCONTROL MECHANISM Nels T. Holmbeck, Chicago, Ill. Application October 8,1942, Serial N5. 461,290

8 Claims. gel. 164-22) My invention relates to a feed control mechanismadapted particularly for accurately controlling the feed of stock, suchas a metal'strip orv band, to the cooperating members of die sets,punching assemblies, or the like.

My invention concerns particularly improvedv operation and control ofstock feed mechanism which is permanently attached to and forms anintegral part of a die set assembly, as for example in the arrangementdisclosed in Dickerman Patent No. 1,968,479, dated July 31, 1934. Inthis type of feeding arrangement, a stationary gripper unit and areciprocating gripper unit cooperate with the movement of the punchelement of a die set to shift the stock band periodically the requiredfeed distance into the die set and to hold it while the die operationsare being performed. 'However, it has been found 'that, in feedstructures of this type, there may be very slight overfeed, orunderfeed, for each feeding operation, and although such error may bevery slight for each feed movement, the error will be so multipliedduring a period of operation of the die set that the incorrect feedingwill result in imperfect die formation of the object to be formed out ofthe stock band.

The important object of my invention is therefore to provide simplemeans for correcting each feed movementof the stock band beforeoperation of the :die set to work on the band. This I preferablyaccomplish by effecting release of both gripper units from the stockband just prior to final closing of the die elements and by providing analigning member on the punch element for engagement with the freed bandto shift it into proper position over the die element for final movementof the punch element into forming engagement with the stock band.

The purposes and advantages of my invention will be clearly understoodfrom the structure shown on the drawings, in-which:

Figure 1 is a side elevation of the inlet end of a die set and the feedmechanism secured thereto; v

Figure 2 is a plan view of the feed mechanism; v Figure 3 is an enlargedsection on plane IlI--III of Figure2, showing the position of thereciprocating gripper unit after a feeding operation;

Figure 4 is a similar section showing the gripper unit about to engagethe stock band for feeding thereof; v

Figure 5 is a section on plane V-V Figures 2 and 3;

Figure 6 is a perspective view of one of the 55 ceivethe shaft 42 forthe raisebars which function to release the gripper unitsfrom the band;and l Figure '7 is an enlarged cross-sectional view of the upper andlower feed rollers of the gripper 1 unit to show the clutch mechanismfor permit ting rotation of=the rolls in only one direction.

The frame of the feed mechanism comprises inner and outer cross wallsI!) and II, and front and rear side walls 12 and I3. Adjacent to theouter cross wall it is the stationary gripper assembly A. This assemblycomprises the shaft I4 extending between and secured to the side wallsl2 and I3 by caps l5 through which extend set screws l6 for holding theshaft against rotation. Extending between the side walls l2 and I3 andmounted on the shaft I4 is the lower feed r011 l1., u 1

At their upper ends the side walls 12- and it have the rectangular slots[8 respectively for the, rectangular bearing blocks l9 which receivethev ends of a shaft 20 on which is mounted the upper gripper roll 2|vwhich extends between the side walls [2 and l3. Set screws 22 hold theshaft against rotation in the bearing blocks.

Extending between the side walls [2 and 13 and across the upper ends ofthe slots I8 is a plate 23 which is detachably secured to the walls asby screws 24. This plate has upwardly extending opposed walls 25 and 26thereon between which is located a pressure bar 21 which, at each end,has a threaded stud 28 extending therethroughin'alignment with thecorresponding bearing block I9. The threaded studs at their lower endsterminate in abutment heads 23 between which and the bearing blocks I9springs 30 are interposed.

Between the side walls 25 and 25 above the pressure bar, a cam lever 3|is secured to a fulcrum pin 32 journalled in the side walls, the camlever having the cam head 33 which, upon downward swing of the lever,will force the pressure bar 21 downwardly for compression of the springs30 and corresponding pressure against the shaft 20 to hold the upperroll 2| in pressure engagement with the lower roll l1. s

The reciprocating gripper unit B comprisesthe side walls 34 and 35connected at their lower ends by cross bars 36 and these side walls aresecured to front and rear guide or carriage frames 31 and 38, as bybolts 39. These guide frames 31 and 38 have guide channels 49 and 4|,respectively, therethrough for receiving the inner guide portions I2 and[3' of the side walls 12 and 13.

The side walls 34 and 35 at their lower ends relower gripper roll 43,

the shaft being locked against rotation by set screws 44. In their upperends the side walls 34 and 35 have the rectangular slots 45 for thebearing blocks 45 which receive the shaft 4'! for the upper gripper roll48, set screws 49 holding the shaft against rotation in the bearingblock.

A plate 50 is detachably secured by screws to the side walls 34 and 35over the tops of the slots 45, and between the side walls 52 and 53 onthe plate is the pressure bar 5d having threaded studs 55 therethroughat its ends terminating in heads 56 between which and the respectiveblocks 46 are located the springs 51. is secured to the fulcrum pin 59journalled in the side walls 52 and 53 and upon downward swing of- Thecam lever 53 the lever the cam head 60 will shift the pressure bardownwardly for pressure exertion of the spring to hold the upper gripperroll 48 for'pressure engagement against the lower roll 43. -By

virtue of the threaded engagement of the studs 55 in the pressure bar 54(Figure'5), and the the threaded engagement of the studs 28 in thepressure bar of the gripper unit A (Figure 1), the desired pressureengagement of the upper gripper rolls with the respective lower gripperrolls can be obtained. After setting of the studs they-are held inadjusted position by lock nuts 6 I.

The front and rear guide frames 31 and 33 for the reciprocating gripperunit 13 have abutment ears t2 and 63 thereon to which rods 64 and 65 arerigidly secured and to extend therefrom through passageways 66 in theears 6! and 68 on the outer end wall I i. Between the opposed ears, therods support compression springs 69'and l0, and the outer ends of therods being threaded to receive adjusting and lock nuts H. The springstend to hold the gripper unit B in its inner position with the nuts Habutting the ears 61 and 5B, and by means of the nuts H the feed travelof the unit B is determined.

The stock band S extends through the feed mechanism between the upperand lower rolls of the gripper units, the rolls of each unit having thecentral portion l2 of increased diameter and of less width than theband, the end portions 13- of the rolls being of lesser diameter so thatthe pressure of the springs against the supporting blocks for the shaftsof the upper rolls will exert prssure against the band to hold itagainst the lower rolls.

Referring to Figure '7, each of the rolls is permitted to rotate only inone direction on its supporting shaft and is locked against rotation inthe opposite direction. Any suitable looking or clutch means may beprovided. As shown,

clutch balls M, urged by springs 15, will lock each upper roll againstcounterclockwise rotation but will permit clockwise rotation thereof,while the clutch mechanism in the lower rolls lock them againstclockwise rotation but permit counterclockwise rotation. Thus, after afeed of the stock band, the rollers on the unit A will hold the handagainst reverse movement, but the rolls on the unit B will roll alongthe band as the'supporting carriage "for the'rolls is shifted outwardly,

and then upon inward-or feeding movement'of the unit B, its rolls willclamp the band for feed thereof during inward movement of the carriage,the rollers of the unit A being then free to rotate.

Adjustably secured to the end wall ll of the feeder structure, are armsTit journalling opposed guide rollers or spools l7 between which theincoming stock band S passes. On the innerrend wall l0 similar guiderolle'rsor spools 18 'are journalled between'which the band travels,

to the end walls l0 and H as by screws 54.

these spools tending to hold the band aligned on its passageway throughthe feeder units. To further guide the band and to hold it aligned withthe gripper rolls, guide member I9 and 86 are provided. As shown, eachguide member comprises upper and lower plates BI and 82 separated alongtheir outer portions by a spacer plate 83, the upper and lower platesalong their inner portions receiving between them the edge portions ofthe stock band, the spacer plates forming guides engaged by the edges ofthe stock band. These guide structures are secured at their ends ASindicated at 85, the guide members are cut away at their inner portionssufficiently to provide clearance for engagement with the band of thecenter portions 12 of the rolls I! and 21, and as indicated at '86, theguide members are cut out along their inner portions to provideclearance for engagement with the band of the center portions 72 of therolls 43 and 48 as the unit B is reciprocated.

Referring to Figures 1 and 3, the die block 81 of adie set supports thevarious die structures D, and the punch block 83 supports the variouspunch structures P. The feed structure is secured to a supporting block89 on the die block by means of screws 95 passing through the end Thedie set with the feed attachment thereon is placed on a punch press bedfor cooperation of the punch press ram with the punch block 88 in amanner well understoodin the art.

At the upper innercorners of the guide frames 37 and 38 forthe feed unit3 are journalled cam rollers 9! and .92 for enga ement by cam plates 93and Q4 secured to and depending from the punch block .88. These camplates are of rectangular cross section and each presents at its lowerend the diagonally extending cam surface terminating in the verticalsurface 96 at the inner edge of the .platesthe width of the plates atthe surface-35 being equal to the distance of the desired feed of thestock hand. Above the surface .196 the. cam plates have the verticalsurlower forward ends of the inclined cam surfaces 95 are in engagementwith the cam rollers so that, upon downward movement of the punch block,the feed unit B willbe shifted outwardly until the vertical surfaces 96receive the cam rollers. Such outward movement ofthe unit B is resistedby the springs 69 and 1B. Duringsuch outward movement of the unitB, thestock band will be held against outward movement by the rolls of theunit A-which are locked against rotational movement, the rolls of theunit B being however free to roll along the stock band. While therollers are being engaged by thevertical surfaces 56, the-punch block 88is moved down sufficiently for punching or forming work on the band. Asthe punch block 88 is then moved up-- wardly the vertical surfaces 96will leave the cam rollers and the camrollers will come into engagementwith the inclined cam surfaces 95 along which they will travel bythe-pressure of the springs 69 and 10 until the unit B is restored toits inner-position. During such inward movement of the unit B, its rollswill be locked against rotation and will grip the stock band to feed itinto the die set, the rolls on the unit A-being then free to rotate.After the feed operation both-sets of rolls will be locked againstrotation .to prevent outward movement of the band from its fed-inposition.

Although great precision is employed in mak ing and assembling the feedstructure, very slight overfeed or underfeed may occur which, for asingle feed operation, may not be material, but which, when multipliedafter a period of operation of the die and feed structure, may causeerror in the formation of the band by the die structures. I havetherefore provided simple and eflicient means for compensating for anyfeed errors and assuring accurate and correct posi-' tioning of the bandin the die structure before the punch or other forming members on thepunch block come into engagement with the band and the die structures onthe die block. This I accomplish by effecting release of the upper rollsof the feed units from the band at the end of the outward movement ofthe unit B, and providing aligning means on the punch block forcooperation with the released band to shift it into its proper positionin the die set. As shown on Figure 1 I mount an aligning pin 98 in thepunch block 88, which pin has a tapered end, and in the die structureadjacent to the feed mechanism L I provide a passageway 99 for thealigning pin. In advance of the aligning pin, the punch block carries apunch pin II!!! for cooperating with a die passageway IUI to punch outthe stock band to provide pilot holes I92 for passage of the aligningpin into the passageway 99, so that the tapered end of the aligning pinmay engage with the band edges around the holes I02 to shift the band,if necessary, to bring the holes I92 into alignment with the passageway99 and thereby set the band in proper position for die operation.

The mechanism forreleasing the upper rolls from the band for operationof the aligning pin, is best shown on Figures 2, 3, 4 and 6. Thereleasing mechanism is in the form of raise bars Hi3, one of such barsbeing shown in perspective in Figure 6. The two bars are supported fromthe guide structures I9 and 89 in alignment with the cylindrical endportions I3 of the rolls in the units A and B, the ends I94 of the barsbeing of a height to extend between these end portions of the rolls whenthe upper rolls are clamped down against the stock band. The middleportions I95 of the bars are received in supporting and guide bracketsI98 secured to and extending from the respective guide structures I9 and80, with the outer end portions I04 of the bars extending between thouter portions 73 of the rolls of the unit A. Between its inner portionand its outer portion each bar has upwardly extending portions I99, theapproaches I II! to these portions I95 being inclined, as clearly shownon Figure 6.

When the punch block 88 is in its upper position and the unit B is inits inner position as shown on Figures 1, 2 and 3, the rolls of the unitI B are displaced from the inner ends of the raise bars I93. When theunit B is shifted outwardly by the cam plates 93 and 94 upon downwardmovement of the punch block, the spaces between the outer portions I3 ofthe rolls on unit 13 will receive the outer ends I94 of the raisebars,'and when the cam rollers 9| and 92 are in engagement with thevertical surfaces 96 on the cam plates, the inclined surfaces III! atthe inner ends of the raise bars will be engaged by the outer portions13 on the upper roll of the unit B, and the inclined surfaces III! atthe outer ends of the raise bars will be in engagement with the outerportions 13 of the upper roll of the unit A. Now, as the punch head ismoved down further to engage the surfaces 91 of the cam plates with thecam rollers 9| and 92, the resulting final movement of the unit B towardthe unit A will cause the inclined surfaces III! to wedge the upperrolls of the units upwardly against the pressure of their pressure barsto release the rolls from the stock band. This released position of theupper rolls is maintained while the vertical surfaces '91 on the camplates remain in engagement with the cam rollers, and while the stockband is thus released, the aligning pin 98 will pass with its taperedend through the hole I92 in the band and will center this hole with thepassageway 99 so that, if there was any error in the feeding of the bandby the feed mechanism, such error will be compensated for and the bandshifted into the proper position for engagement by the forming memberson the punch block, the operation of the aligning pin taking place justbefore the punch pin I and other punch or forming members on the punchblock come into engagement with the band and the cooperating dieelements on the die block 81. The punch pin I09 then punches the hole inthe stock band for cooperation with the aligning pin 98 after the nextfeed operation of the feed mechanism. Such feed takes place as the camplates are withdrawn from the cam rollers as the punch block movesupwardly. As the punch block starts to move upwardly, the aligning pin98 will remain in the hole I92 until the vertical cam surfaces 91 on thecam plates are withdrawn from the cam rollers on the unit B, themovement of the cam rollers from the surfaces 91 to the verticalsurfaces 96 permitting the outer portions I3 of the upper roll of theunit B to leave the inclines I91 at the inner ends of raise bars so thatthe bars are free to be shifted inwardly by the pressure of the upperroll of the unit A against the outer inclines I01 on the bars, thepressure bars on the units A and B being then free to reset the upperrolls against the stock band for gripping of the band between the rollsof the unit B so that, as the cam rolls on the unit B come intoengagement with the inclined cam surfaces on the cam plates, the springs69 and I9 may shift the unit B to its inner position and to feed theclamped band into the die set. On the raise bars, the spaces between theprojections I06 are sumciently longer than the width of the supportingbrackets I98 so that the bars may have sufficient longitudinal movementto be shifted into wedging engagement with the upper rolls during thefinal outward movement of the unit B and to be freed from the rollsduring inward or feeding movement of the unit B. When a new stock bandis to be fed intothe structure, the punch head 89 is brought down untilthe surfaces 9'! 0n the cam plates will just come into engagement withthe cam rollers on the unit B and before the punch pin I99 reaches itscooperating die element. The upper rolls of the units A and B being thenraised, the end of the stock band can be fed in past the die passagewayII but short of the passageway 99 forthe pin 99. Then upon finaldownward move ment of the punch block, the punch pin will punch in theband a hole I92, shown in dotted lines on Figure 2, and when the punchblock is again raised and the unit B is shifted inwardly for feeding theband, this hole I92 will be brought into registration with the diepassageway 99 for aligning cooperation with the pin 98 when the punchblock is again brought down for outward movement of the unit B andraising of the upper rolls of the units from the band.

' I thus provide simple and efficient means in connection with feedmechanisms of the type described which will compensate for any feederrors and assure accurate alignment of the stock band in the die setbefore any die operation on the band. I do not however desire to belimited to the exact structure, arrangement and operation shown anddescribed as changes and modification may be made without departing fromthe scope of the invention.

I claim as follows:

4 1. In a die set, cam means on one of the cooperating and relativelymovable members of the set, a supporting frame secured to and extendinglongitudinally from the other of said members, a carriage movablymounted on said supporting frame and having a part for engagement bysaid cam means, stock gripper means on said carriage free to moverelative to the stock upon outward movement of the carriage by said cammeans, spring means for shifting said carriage inwardly upon releasethereof from said cam means, said gripper means during movement of thecarriage by said spring means being effective to grip the stock wherebythe stock is fed into the die set, means effective during the finalmovement of said carriage by said cam means for entirely disconnectingsaid gripper means from the stock for free longitudinal movement thereofin either direction, and means on the die set for cooperating with thereleased stock to correct for any overfeed or underfeed thereof and toaccurately align the stock in the die set just before the stock isworked on by the die set members.

2. In a die set, cam means on one of the cooperating and relativelymovable members of the set, a supporting frame secured to and extendinglongitudinally from the other of said members, a carriage movablymounted on said supporting frame and having a part for engagement bysaid cam means, stock gripper means on said carriage free to moverelative to the stock upon outward movement of the carriage by said cammeans, spring means for shifting said carriage inwardly upon releasethereof from said cam means, said gripper means during movement of thecarriage by said spring means being effective to grip the stock wherebythe stock is fed into the die set, means effective during the finalmovement of said carriage by said cam means for entirely disconnectingsaid gripper means from the stock for free longitudinal movement thereofin either direction, means on the die set for punching pilot holes inthe stock, and alinging means on said die set cooperable with said pilotholes while the stock is free of the gripper means for compensating forany overfeed or underfeed by the gripper means and to properly align thestock in the die set before the stock is worked on by the die setmembers.

3. In a die set a supporting frame secured to and extending outwardlyfrom one of the die set members, a gripper unit movable on said frameand having gripping means for gripping stock to be fed into the die set,cam means on the other member of the die set effective during closuremovement of the die set members to shift said gripper unit outwardly forgripping engagement with the stock, said cam means being furthereffective to overshift said unit outwardly during the end part ofclosure movement of said die members, means effective during suchovershift of said unit for entirely releasing the gripping means fromthe stock for free longitudinal movement thereof in either direction,and means effective during the fore part of the final movement of saiddie members toward each other for engaging with-the released stock toeffect movement thereof to correct any overfeed or underfeed thereof bythe gripper unit and to accurately align the stock in the die setmembers.

4. A die set having stock feed mechanism thereon in the form of apermanent attachment, means controlled by the closing and openingmovements of the die set members for effecting operation of the feedmechanism to feed stock into the die set, means effective just beforefinal closure movement of the die set members for entirely releasing thefeed mechanism from the stock for free longitudinal movement thereof ineither direction, and means on the die set members for cooperation withthe released stock to correct any overfeed or underfeed of the feedmechanism and to correctly position the stock before engagementtherewith of forming structure on the die set members.

5. A die set comprising members movable to open or closed position, feedmechanism forming a part of the die set, means controlled by the closingand opening movementof the die set members for controlling the feedmechanism to feed stock between the die set members, punch means for thedie set members for punching pilot holes in the stock during closuremovement of the members, means effective just before final closuremovement of the die set members for effecting entire release of the feedmechanism from the stock for free longitudinal movement thereof ineither direction, an aligning pin on one of the die set members and apassageway therefor in the other die set member, said pin just beforefinalclosing movement of the die set members being projected through oneof the pilot holes and into said passageway for shifting the stock afterrelease of the feeding mechanism therefrom whereby to correct for anyoverfeed or underfeed of the stock by the feeding mechanism and toaccurately align the stock between the die set members before saidmembers are finally moved to closed position.

6. A die assembly comprising a die block element and a punch blockelement, a supporting frame extending from the die block element, astationary gripper unit on said supporting frame and a feeding gripperunit reciprocable on said frame, cam means on said punch block memberengageable with said reciprocating unit to shift it outwardly uponclosure movement of the die block and punch block members, spring meansfor shifting the reciprocating unit inwardly during opening movement ofthe die and punch block assemblies, an upper and a lower-gripper rollfor each unit and spring means tending to urge said rolls together forclamping a stock band to be fed by the unit, said rolls being adapted torotate in only one direction whereby the rolls on the stationary unitwill hold the stock band against outward movement and the rolls on thereciprocating unit may roll along the band during outward movement ofthe unit and to grip the band during inward movement of the unit forfeed of the band, means effective during the final outward movement ofsaid reciprocating unit for entirely releasing the gripper rolls fromthe stock band for free longitudinal movement of the band in eitherdirection, and coopcrating means on said die and punch block members forengagement with the released stock band to shift it for correction ofany overfeed or underfeed by the feeding mechanism and to accuratelyalign it for working engagement by die and punch structure on said dieand punch block members.

7. A die assembly comprising a die block element and a punch blockelement, a supporting frame extending from the die block element, astationary gripper unit on said supporting frame and a feeding gripperunit reciprocable on said frame, cam means on said punch block memberengageable with said reciprocating unit to shift it outwardly uponclosure movement of the die block and'punch block members, spring meansfor shifting the reciprocating unit inwardly during opening movement ofthe die and punch block assemblies, an upper and a lower gripper rollfor each unit and spring means tending to urge said rolls together forclamping a stock band to be fed by the unit, said rolls being adapted torotate in only one direction whereby the rolls on the stationary unitwill hold the stock hand against outward movement and the rolls on thereciprocating unit may roll along the band during outward movement ofthe unit and to grip the band during inward movement of the unit forfeed of the band, means effective during the final outward movement ofsaid reciprocating unit for entirely disengaging the gripper rolls fromthe stock band to release the band for longitudinal movement in eitherdirection, a punch pin on the punch block member for punching pilotholes in the stock band, a tapered aligning pin on the punch blockmember engageable in one of the pilot holes while said stock band isreleased and before engagement with the stock band of the punching pinfor shifting the stock to correct any overfeed or underfeed by thefeeding mechanism to properly align the stock between the die and punchblock mem bers.

8. A die assembly comprising a die block element and a punch blockelement, a supporting frame secured to and extending outwardly from thedie block element, a stationary gripper unit on said supporting frameand a reciprocating gripper unit on said frame, upper and lower gripperrolls for each unit between which a stock band is to be shifted forfeeding between the die and punch block elements, yieldable clampingmeans engaging the upper rolls of the units for clamping of the stockband, the rolls of said units being capable of rotating in only onedirection whereby the rolls of the stationary unitwill hold the stockband against outward movement and the rolls on the reciprocating unitmay roll along the band during outward movement of the unit but willgrip the band during inward movement of the unit, cam means on saidpunch block element having a cam surface engageable with thereciprocating unit to shift it outwardly along the stock band while theband is being held by the stationary unit, spring means for returningsaid reciprocating unit inwardly when said cam surface is beingwithdrawn therefrom, the movement of said reciprocating unit by said camsurface being equal to the desired distance of feed of the stock band,another cam surface on said cam means operative after movement of saidreciprocating unit by said first mentioned cam surface to effect aslight further outward movement of said reciprocating unit, raise barslongitudinally movable on said supporting frame and having inclinedsurfaces at their ends for engagement with the upper rolls of the unitsto raise them entirely away from the stock band during such finaloutward movement of the reciprocating unit whereby the stock band willbe entirely released from the units, a punch pin on said punch blockelement for punching pilot holes in the stock band, a tapered aligningpin on said punch block element spaced from said pilot punch pin adistance corresponding to the desired feed distance of the stock band,said aligning pin being engageable in a pilot hole in 1 the stock bandwhile said stock band is held released from the feeder units forshifting of the stock band to correct any underfeed or overfeed by theshifting unit whereby to properly align the band for punching thereof bythe pilot punch pin.

NELS T. HOLMBECK.

